Charging the battery of a motor vehicle requires the battery to pass a current that is typically equal to 14 A, and to do so for several hours.
For practical reasons, it is thus advantageous for the user to plug the battery of the motor vehicle into a standard domestic socket outlet that is standardized for 16 A.
Theoretically, that type of socket outlet presents intrinsic characteristics that enable it to deliver a current that is less than or equal to 16 A for a standardized duration.
However, that type of socket outlet satisfies standard requirements that are defined for ordinary domestic uses for which the current delivered is usually less than 14 A or 16 A, with the socket outlet being used at periodicities and for durations that are less than the periodicities and the durations that are necessary for charging the battery of a motor vehicle.
Furthermore, in practice, the intrinsic characteristics of the socket outlets installed in the homes of users may vary from one socket outlet to another, and may also vary over time. It is impossible to know such characteristics with certainty.
It is also possible that the user is confronted with a socket outlet that does not comply with the standard.
Such uncertainty concerning the intrinsic characteristics of socket outlets, and thus concerning suitability for delivering a current of 14 A or more for several hours, and in regular manner, is not acceptable since it jeopardizes the safety of people and of installations.
A novel domestic application such as charging an electric vehicle may stress socket outlets to the limits of standard characteristics, and consequently requires accurate knowledge of the type and of the quality of the socket outlet used in order to take advantage of the maximum capacities of the socket outlet without damaging it, and in particular to take advantage of the maximum current that the socket outlet is adapted to deliver continuously without being damaged.
The socket outlet described in document FR 2 943 468 provides a first response to that problem in that it includes identification means for supplying the user with a pilot signal that is representative of data about the appliance plugged into the socket outlet. The pilot signal is a light signal that informs the user that the socket outlet is not suitable for use with the appliance.
A drawback of that socket outlet is that it cannot give information directly to the appliance that is plugged therein about the electrical signal delivered by the socket outlet.
The appliance thus cannot adapt its operation to the socket outlet to which it is plugged.
Furthermore, the safety of the installations and of the people is not guaranteed since an inattentive user may plug an unsuitable appliance to the socket outlet.
Documents FR 2 949 280 and WO 2007/072581 disclose electrical assemblies each comprising a socket outlet and an electric plug including means that enable the socket outlet to recognize the plug so as to allow the electrical signal to pass from the socket outlet to the plug.
Documents EP 2 230 729 and EP 0 448 084 also disclose electrical assemblies each comprising a socket outlet and an electric plug including means that enable the socket outlet to recognize an absence of contact or an electrical contact fault between the socket outlet and its associated plug.
However, none of the assemblies enable the socket outlet to generate a signal that informs the electric plug about the maximum current that the socket outlet is adapted to deliver without being damaged.